Polyamide resin suspensoids



United States Patent 'POLYAIVIIDE RESIN SUSPENSOIDS Harold Wittcoff, Minneapolis,Minn., assignor to General Mills, Inc, a corporation of Delaware N0 Drawing. Application August 8, 1956. Serial No. 602,916

8 Claims. (Cl. 260-292) The present invention relates to suspensoids of certain mixtures of polyamide resins and is a continuation-inpart of co-pending application Serial Number 282,699, filed April 16, 1952. These suspensoids possess unusual properties which will be pointed out more fully hereinafter.

Heretofore heat-seal compositions which seal to plastic films have not been generally available. In order to obtain a heat-seal composition which seals, for example, to a vinyl plastic film, or to a polyvinylidene chloride containing film it has been necessary to add plasticizers to the heat-seal composition. As a matter of fact, it has been necessary to add these plasticizers to such an extent that the film from the heat-seal composition becomes tacky and blocks under normal storage conditions. Thus such compositions are virtually useless as heat-seal products. This follows since heat-seal compositions are usually coated on paper, the coated paper being then stored either in huge rolls or as stacked sheets. In either case tremendous pressures are developed on the heat-seal surfaces. In addition, during the summer time or in the warm climates the temperature of the storage room may be as high as 5060 C. and the humidity may approach 100%. A good heat-seal composition must not block under such severe conditions, and at the same time should are highly plasticized in order to make them seal to films such as vinyl films, they become tacky and do not meet the severe blocking requirements outlined above. The suspensoids of the present invention, however, are readily coated on a wide variety of surfaces to provide fast drying films which are not tacky, as will be shown more fully hereinafter, even under conditions where many other heat-seal compositions block. In addition to being nonblocking, the suspensoids of the present invention permit heat-seals over wide temperature ranges, starting at 70 C. Of greatest importance, however, is the fact that in combination with these excellent properties of elongated heat-sealing range and lack of blocking, the suspensoids seal to a wide variety of surfaces, including vinyl plastic films, polyvinylidene chloride-containing films, cellulose acetate films, rubber hydrochloride films, metal and glass. Of particular merit is the fact that the compositions embodied in the present invention provide seals for uncoated cellophane, i. e., the type of cellophane frequently referred to as P. T. or plain transparent cellophane. There are many heat-seal materials which provide seals for coated cellophane particularly when the cellophane is coated with nitrocellulose compositions. There are very few, if any, heat-seal compositions, however, which can be used to bond uncoated cellophane. In addition to providing seals for the aforementioned substances, the suspensoids also provide bonds for cloth, asbestos, metal foils of all sorts, rubber lacquered and enameled surfaces, floc, and in general, for a wide variety of surfaces to which it is ordinarily difiicult to make heat-activated bonds.

It is therefore an object of the present invention to provide novel polyamide resin suspensoids which have the variety of properties described above.

The polyamide resin suspensoids of the present invention are composed of two polyamide resin components: the first is a high melting polyamide resin derived from a mixture of polymeric fat acids and an additional polycarboxylic acid, the latter having at least two carboxyl groups which are separated by at least 3 and not more than 8 carbon atoms. Typical of such'polybasic acids are the aliphatic acids, glutaric, adipic, pimelic, suberic, azelaic, and sebacic, and the aromatic acids, terephthalic, and isophthalic acids. The melting point of the copolymer resin may vary within the range of 130-210 C., depending upon the particular reactants, relative ratios thereof, as well as reaction conditions. Desirable copolymers from adipic acid melt at ZOO-205 C.; from sebacic acid at 180185 C.; and from terephthalic acid at l65l70 C. In general these polyamide resins are prepared from a mixture of polycarboxylic acids containing from -98% by weight of fatty polymeric acids and from 215% by weight of the additional polycariboxylic acid. The polyamides may be made by the condensation of this mixture of polybasic acids with an aliphatic polyamine such as ethylene diamine in accordance with the teachings of Cowan et a1. Patent 2,450,940.

The second component of the mixture of polyamides is a polyamide derived from polymeric fat acids and polyamines having at least 3 atoms intervening between the amino groups principally involved in the amidification reaction. These atoms may be either carbon atoms or hetero atoms. These polyamides melt below C. and generally melt within the range of 2575 C. They are all tacky materials possessing a high degree of cold flow.

The polymeric fat acids employed in preparing the polyamide resins are those resulting from .the polymerization of drying or semi-drying oils, or their free acids or the simple aliphatic alcohol ester of these acids, i. e., sources rich in linoleic acid. Suitable drying or semidrying oils include soybean, linseed, tung, perilla, cottonseed, corn, sun flower, satfiower and dehydrated castor. Suitable fatty acids may also be obtained from tall oil, soapstock, and other similar material. In the polymerization process for the preparation of the polymeric fat acids the fatty acids with suificient double bond functionality combine for the most part, probably by a Diels- Alder mechanism, to provide a mixture of dibasic and higher polymeric fat acids. ferred to as dimers, trimers, etc. In place of this method of polymerization, any other method of polymerization may be employed whether the resultant polymer possesses residual unsaturation or not. Thus, the term polymeric fat acids as used herein is intended to include the polymerized mixture of acids, which usually contain a predominant portion of dimer acids, a small quantity of trimer and higher polymeric fat acids and some residual monomer.

It has been postulated that the structural formula of the dimer acid from linoleic acid is as follows:

H H $2? HOOC (C 2)aCH HC-(CH2)4CH;

HC-C(CH2)4CH3 The trimer is then formed from the dimer by a Diels- Alder reaction with linoleic or linolenic acid at either of 2,824,848 Patented Feb. 25, 1958 These acids are often re 31 a the double bondslshown in the above formula. It will be appreciated 'that the polymeric fat acids will, as a practical matter, result from fatty acid mixtures that contain a preponderance of linoleic acid since the only naturally occurring"polyeunsaturated .acid available in large quantities is 'linoleie' acid; It should also ;be: appreciated that since liuoleic acid occurs in nature as a complex mixture mevery instance, .it is available in'various degrees of puritysrangingfrom relatively expensive pure linoleic acid that has been laboriously purified to crude sources suchas'ta'lloil and soap-stock Which contain substances other. than'fatty. acids. In actual practice linoleic' acid rich mixtures" of fatty acids are used to prepare the polymeric fat :acids. One method of obtaining thelinoleic acid rich fatty acids is by separating amajor portion of V the oleic and saturated fatty acids from any convenient and economical source of fatty acidshaving a high iodine I value. In. addition, polymeric fatacids are readilyavailable commercial'products. One such product is. Empo 'l-022 as sold by'Emery Industries, Inc. Typical'of the polyamines which may be used are diethylene triamin'e,triethylene tetramine, tetramethylene pentamine, :1 ,4-diaminobutane, l,3=di'aminobutane, hexamethylene 'diamine, .diacetone diamine, 3-.(N-isopropylamino.)propylamine, 3,3'-imino-bispropylamine and the like.

'For the suspensoids of the present invention the low melting polyamide resin must be present at least to .the

' extent of of the composition. Furthermore, when a small quantity of the low melting resin is employed, it is preferred that the melting point of the higher melting copolymer resin be not in excesstof 1609C. On the other hand, the low melting resin should notbe present to an extent greater than.80% of the composition to avoid tacky. films which would not be acceptable as heattween the melting points ofthe resins and the relative In general it is preferred quantities of each employed. to employ from 40-60% of the low melting tacky resin and between.60% and 40% of the higher melting scopolymer resins. r i ,In' the preparationof the polyamide resins described amine groups and the relativenumber of these freeamine "groups is referred to as the amine, number. 'As used herein, the amine number may be defined as the milli grams of potassium hydroxide equivalent to the free amine groups in one gram of productf'lhe polyamide resins employed in the" present invention must have .an amine number of at least .5, and preferably should have an amine. number of at least 10. The amine numbers of th polyamides may be as high as 100 or morei, This is especiallyatrue when the resins are prep'ared'with amines V f .such as diethylene triamine, whichjcontainsa secondary amine group which presumably does not enter'into the reaction.

In resins'prepared from ethylene: diamine'th'e amine number is readily controllable, and for practical purposes need not exceed 15. Actuallya higher amine number. is not detrimental in the presentir vention'but it is of no advantage. This applies alsoto the low melting polyamide resins which are prepared'with amines such as V .diaminobutane. 1 When amines such as .diethylene t'ri amine are used where as' previously indicated these'cndary amine gnoupsdqnot enter into the reaction, a ary ig umbai rr eiw above it is important that thefinal compositions have free 7 'The preparation of suspensoids'from these mixed polyamides involves simply the melting ,offthe polyamide mixture, followed by the addition of water. containing a small amount of acid. The entire mixture is agitated vigorously. If the melting point of the mixture'of polyamide resins is above 100 C., as isfrequently the case, it is desirable to preparethe suspensoid under pressure such that the aqueous phase may be above 100 C.

A wide variety of acids may. be employed to effect this dispersion. Suitable acids "include formic, acetic, pro pionic, butyric, monochloracetic, hydrochloric, phosphoric, boric, fumaric, lactic, maleic, oxalic, tartaric,

glycollic,-b'enzoic, succinic, terephthalic, gallic, and the like. Only a small quantity of-acid is necessaryto'efiect' dispersion. The quantityof-acid may be only a small portion of that which would be required to neutralize the free amine groups in the" polymer-or in the polymer mixture in those cases where the total amine number is greater than 20. In the case of polymers or polymer mixtures having amine numbers below 20,.the quantityof acid employed should be that which would neutralize. a substantial portion of the amine groups. Where the polymers .or polymer mixtures have amine numbers -below 10, the quantity of acid employed should be about enough ,to.completely neutralize .the amine groups -ln general, it maybe stated thatsuflicient acid should be employed to neutralize a quantity. of amine groups in the. polymer mixture equivalent to an amine number of!" 7 from 7 to 20. The optimum quantity of acid for any particular polyamide resin mixture and for each specific acid used can be readily determined. a

When larger quantities of acid than thosedescribed being preferred :are employed with mixtures containing high, amine numbers, colloidal solutions or gels may beformed. This is particularly true where the amine num ber of the mixture is above 20. These colloidal -solu-' tions or gels are useful in various applications, but-in general are less desirable thanthe suspensoids described 7 above. ,This phenomenon, however, may be made use of in controlling the viscosity of the suspensoid, partic- As alternative method of 'formingjthe suspensoids the p following are possible. The. individual :polyamides may be separately dispersed in aqueousacid to form separate suspensoids and these suspensoids may then-be mixed together. Furthermore, in place of employing a mixture of polyamides, each of which has an amine number, a m xture of polyamides may be employed in which only a one of the polyamides has any'appreciable amine number,

7 thispolyamide being the means whereby thewother -polyamide which has substantially no amine number is dis persed in water. 7

Since the suspensoids of the present invention "are; i 7 cationic, they are compatible with a wide variety of V, cationic or non-lonic. dispersions which maybe'usedto m y- -PI P fi -S of :the present suspensoids. Disf persionswith whichl-thesesuspensoids are compatible i jclildeaa wideva'riet'y of elastomeric ,substan'ce sQpartic-f I ularly natural and syntheticrubber laticessof all sorts; j "such as natural rubber latex, polyisobutylenelatex hutaal diene latexgcbutadiene-lst-yrene cop ly-merJatex, isoprien'e fl V latexfchloroisoprene latex, .acrylonitrile-butadieneicopoly; t merlatex; c-ompatible dispersions; also include resirif, emulsionsor -suspensoidssuchas thosederivedfrompol vinyl acetate, polyvinyl butyral, polyfiuorethylenaafterpeneresins,acrylicrresins such as spolyacrylonitrile;.polymethytmethacrylate and .the like, halogen-containing resinssuch as polyvinyl-ehloride, phenolic resins such-as p phenol-formaldehyde resins, vegetable and mineral oils,- asphalt, and the like.

Of particular importance is the compatibility of these polyamide resin suspensoids with polyvinyl acetate emulsions. The suspensoids serve to improve the water resistance of the polyvinyl acetate emulsions. They also serve to plasticize the emulsions and to decrease the tack of the emulsions. For this reason, blends of polyarnide resin suspensoids and polyvinyl acetate emulsions are particularly desirable.

In addition to being compatible with a wide variety of dispersions described above, the present polyamide resin suspensoids may be used as a means of dispersing other materials which are non-dispersible by themselves. Thus non-dispersible materials may be included in the mixture of resins and these may be dispersed along with the polyamide resins themselves. Included among these nondispersible materials are plasticizers such as a great variety of sulfonamides, for example N-ethyltoluenesulfonamide; phosphates, such as tributyl phosphate, tricresyl phosphate, triethyl phosphate; and other plasticizers, such as dibutyl phthalate, dioctyl phthalate, dicapryl phthalate, dibenzyl sebacate, 2-ethylhexanediol- 1,3; a great variety of rosin derivatives; a great variety of alkyd resins such as glycerol-castor oil acids-sebacic acid, alkyd, dioctyl sebacate, tall oil, chlorinated hydrocarbons, phenolic resins, coumarone indene resins, and a great variety of commercial plasticizers of which the hydrocarbon and terpene types are important.

Tackifiers may also be dispersed along with the polyamide resins. Suitable tackifiers include rosin, disproportionated rosin, hydrogenated rosin, polymerized rosin, rosin from tall oil; the glycol, glycerol, pentaerythritol, 2,2,6,6-tetramethylol-cyclohexanol and other polyhydric alcohol esters of these rosins; maleic modified rosins, and rosin esters, methyl and other alkyl esters of rosin, limed rosin, rosin alcohols and their esters, phenolic resins, tri- (p-tert-butylphenyl)phosphate, coumarone-indene resins, chlorinated naphthalene, furfuryl alcohol, blown castor oil, and the like.

In addition to the variety of the materials listed above a great variety of water-soluble or water-dispersible substances may be incorporated in the suspensoids. These materials include all types of polyvinyl alcohols; polyvinyl alkyl ethers such as polyvinyl methyl ether; polyalkylene glycols such as polyethylene glycol, and their esters and ethers; cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxy ethyl cellulose and carboxy methyl cellulose; starch derivatives such as carboxy methyl starch, modified starch, dextrin; and various gums such as karaya, locust bean and tragacanth gums, Irish moss, and the like. These materials may be added directly to the suspensoid after it has been formed or else may be incorporated into the water used in the formation of the suspensoid. The latter procedure is preferable when large quantities of the additives are to be used, whereas the former procedure works well for smaller quantities. These materials for the most part serve not only to increase the viscosity of the suspensoid but also to provide a firmer adhesion of the suspensoid film to a surface thus preventing cracking or dusting.

This invention can be illustrated further by reference to the following examples in which all parts are expressed as parts by weight.

HIGH MELTING COPOLYMER RESINS Example 1 (a) For this preparation polymeric fat acids derived from a linoleic acid rich fatty acid mixture by polymerization at about 325 C. were used having the following Saponification equivalent 291.1

A mixture of these polymeric fat acids (437 parts) oleic acid (17.5 parts) and sebacic acid (48.4 parts) were heated to 130 C. after which 94.2 parts of 67.5% ethylene diamine were added at a rate such that the temperature of the vapor escaping from the reaction did not exceed 99 C. The reaction vessel was fitted with a fractionating column so that the water vapor would be removed whereas the ethylene diarnine remained in the reaction vessel. After all the ethylene diamine had been added, the pot temperature was maintained at 200 C. for '3 hours. During the last hour of reaction the apparatus was maintained under vacuum. The product was then poured over Dry Ice and allowed to solidify. It had the following properties:

Melting point (ball and ring) C 183 Gel time at 200 C minutes 14 Color (Gardner) l1 Penetration hardness 2.5 Amine number 16.0 Acid number 6.3

(b) A second high melting copolymer was prepared according to the procedure of 1(a) using the following ingredients:

Viscosity at 25 C. (Gardner-Holdt) AB The viscosity of these materials was determined in a 25% solution of phenol-butanol (1:1). The color was determined in a 35% solution in toluene-butanol (1:1).

(c) Another typical copolymer resin which may be used in the invention was prepared in the manner described in Example 1(a) from the following ingredients:

Parts Polymeric fat acids (composition indicated in Example 1(a)) 40.0 Oleic acid 29.2 Adipic acid 11.7 Ethylene diamine (75.6%) 52 The product had the following properties: Melting point (ball and ring) C 176.5 Acid number 8.0 Amine number 14.6 Color (Gardner) 11-12 Penetration hardness 4.4 Gel time minutes 30 Viscosity (Gardner-Holdt) A-l LOW MELTING POLYAMIDE RESINS Example 2 The materials employed were as follows:

Parts Polymeric fat acids (composition indicated in Example l(a)) 40.0 Oleic acid 2.4 Diethylene triamine (95.6%) 7.48

' The materials were placed in the same type of apparatus described in Example 1(a) and were heated slowly to a temperature of 200 C. with vigorous agitation. The heating was controlled so that the temperature of the escaping vapor did not exceed C. The reaction lowed to cool. dispersion of medium 7 of 40% resulted.

. 7 mixture was maintained at 200 C. for 3 hours andduring the last hour vacuum was employed. At the end of the reaction period the vacuum .was-released'and the prodnot was cooled. The product had the following properties: i

Melting point (ball and ringli c; 46.5

Color (Gardner) 10-11 Viscosity at25 C. (Gardner-'HoldtL B-C Acid number j 5.2

Amine number 86 Gel time at 200. 'C Greater than 30 min.

' Example 3 Seven hundred parts of the copolymer resin described in Example'l b) were melted and to the molten mixture were added 300 parts of the soft polyamide resin described in Example 2. The mixture'was heated to 190 7 C. after which 1500 parts of hot water containing 10 parts of'glacial acetic acid were added with'vigorous stirring. The stirring was continued for'15 minutes during which time the heat was removed and the dispersion was al- There resulted a white, smooth, creamy viscosity and a solids content of40% V r r Example 4 Six hundred parts of the copolymer resin described in Example 1(12) were melted and to the molten'mixture were added400 parts of the soft polyarnide resin 'described in Example 2. The mixture was heated to. 190 C. after which 1500 parts of Water containing 9 parts of glacial acetic acid wereadded with vigorous; agitation. The source of heat was removed and the agitation was allowed to continue for 15; minutes. A smooth, creamy dispersion with a solids content of 40 resulted.

Example 5* 1 in Example 1 (b) were me'lted and to the melt were added v 120 partssof the soft polyamide resin described in Ex-' The procedure. described in Example 4 was repeated using 500 parts of the copolymer resin, 500 parts'of the soft resin, 1500 parts of water and 9 parts of glacial acetic acid. Again a smooth dispersion with a solids content Example 6 V 4 V The procedure of Example 4 was repeated using 400 parts of the high melting copoly mer resin and 60 parts of thesoft resin together with 1500 parts of water and 8.5 parts of glacial acetic acid. ,There resulted a smooth creamy dispersion with a solids content; of 40% and an "acid number of 6. 3. The pH of the dispersion was 7.66.

Example 7 procedure of Example 4 wasvrepeated using 300 a parts of the high melting copolymer resin and 700 parts of the soft resin together with 1500 parts of water and 7.5 parts of glacial acetic acid. Again a smooth creamy dispersion with a solids content of 40% resulted.

' -Examplezg 7 Eight hundred parts-of the polyamid resin described in- Example 1 (b) were melted and to the resin were added 1200 parts of the soft polyarnide resin described in Example 2. This mixture was heated to 190 C. and was agitatddstrongly'while 3000parts of'hot water'were added. Together the waterwere added 18parts of glacial acetic acid and -200 parts of 50% dodecylamine acetic acid and to add the dodecylamine acetate solution Q with stirring'a'ft-er the initialdispersion is made Example} "number of 5.0.

and complete compatibilitywas demonstrated; The prodnot had a solids content of 42.7%

Example 10 H a 'T o 1000 parts of the dispersion describedfin Example 6 were added 250 parts of a 32% cationic water dispersion of a methaerylic resin. hour to obtain a completely compatible material. i

' Example 11 i I80 parts of the copolymer polyamide resin described ample 2. To this melt were added 60 parts of a plasticizing and tackifying material composed essentially ofa monoglyceride of a'mixt'lire of fatty and rosin acids (30:70). The melt was heated to 190 C. and 555 parts of warm water containing 2.7 parts of glacial acetic acid were added'with vigorous stirring. A low viscosity dispersion resulted with a solids content of 39% and an'a'cid Example 12 V A melt of 600 parts of the polyaniide resin'described in; Example 2 and 400 parts of the polyamide resin described in Example 1(b).w,ere heated to 190- C. Thereafter-a mixture of 1800 parts of water, 200 parts of low viscosity polyvinyl alcohol and"8.5 parts of glacial acetic acid were added to the molten resin. mixture with vigorous stirring.

The water solution was heated almost .to .the boiling point 7 prior to addition. A smooth viscous 'dispersion'resulted. The polyvinyl alcohol maybe added to the'dispersionof resins after the dispersion has been made if desired;

a 7' Example 13 v e A low melting polyarnide resin was prepared from 375 parts polymeric fat acids derived from'a linoleic acid'rich fatty acid mixture: by polymerization at about 325C.

containing about dimertdi-linoleic acid), 30 parts oleic'acid and parts diethylene triamine according to a A high melting copolymer resin was prepared as in Ex ample 1 in which parts polymeric fatacids derived.

from a linoleic acid fatty acid mixture by polymerization at about 300 C., containing about 65% dimer ('di-lino-.

leic acid),.3 parts oleic acid, 10-.parts sebacic acid and 12 parts ethylene diamine resulted in a resin having the following properties; 7 V a Melting point C Gel. time minutes 9 Color .Acid number" 7 13.0

Amine number acetate Sams ns smooth creamy-dispersion resulted. I

i lt is also possible tokdisperse the mate'ri'al usingo'nly'the Example 15;

400-parts of the highmelting-resin shown in Example 7 :14 were melted and 60 parts of the soft resin shown in .To;670 parts of. the dispersion described in Examplefi I were added 97.1 parts of a polyvinyl acetate emulsion of 55% solids content. The resulting mixture was stirred Example 13 added to the'molten mass; The-mixtureof a 1 the two resins was then heated to 200 Cfan'd l500 parts of'water containing 9 parts glacial acetic acid were added with vigorous agitation. A: smooth creamy dispersion containing'41% solids and havingan acid number of 6.0

and a pI-Iof 7.77 resulted. e

The mixture was stirred for 1 9 Example 16 1000 parts of the high melting polyamide resin of Example 14 were melted and added to 1000 parts of the softer polyamide prepared as shown in Example 13. The mixture was then heated to 190 C. and agitated vigorously during the addition of 3000 parts water, 18 parts acetic acid and 200 parts of a 50% dodecylamine acetate solution in water. This procedure resulted in a smooth creamy dispersion.

Example 17 Sixty parts of the resin prepared as shown in Example 13 were mixed with 40 parts of the resin shown in Example 14 and the mixture heated to 190 C. 160 parts Water, one part acetic acid and 20 parts low viscosity polyvinyl alcohol were added to the molten resin with added heat and vigorous agitation. This resulted in a smooth creamy dispersion.

Example 18 Suspensoids similar to those described in Examples 3, 4, 7, 8, 10, 11 and 12 when prepared from a high melting copolymer resin as shown in l (a) and a low melting copolymer resin as shown in Example 13 with equal ease and success and in each case a suitable dispersion resulted.

The blocking resistance of the compositions described in Examples 3, 4, 5, 6 and 7 was tested by the standard TAPPI test T-477M477. The suspensoids were coated on label paper at 4 pounds per ream (500 sheets, 20 x 25 inches). The blocking tests were run face to back at 60 C., 100% relative humidity, and 1 pound per square inch for 24 hours. The tests were carried out in desiccators in order to insure an exact and constant humidity. The products gave blocking under these conditions. By way of comparison, a number of standard heat-seal compositions widely used in the trade blocked under similar conditions to the extent of 10100%.

These compositions were tested for the sealing range. In the determination of the sealing range the object is to discover whether a seal holds at the actual temperature at which it is formed if tension is applied immediately. Ordinarily the heat will melt the composition and a seal will form as the molten material solidifies. For many purposes, however, tension is applied as soon as the resin is softened or melted, and it is necessary that the seal hold at the actual temperature at which it is made. In order to test this property, a testing device was assembled in which a seal was prepared by inserting two 3" strips of label paper between electrically heated jaws. The amount of heat entering the jaws is controlled by a variable transformer and the temperature of the jaws is measured accurately by thermometers inserted into them. The seal is made by stepping on a lever which causes a weight of 8 pounds per square inch to be applied to the seal. The upper strip of the paper which contributes to the seal is held rigid in a vertically upward position. The lower strip is held vertically downward and a 35 gram weight is attached to it. This is set up prior to the time the seal is made so that the 35 gram tension is actually applied to the 3" seal as soon as the jaws are released. For purposes of standardization and to make sure that equilibrium has been established, the jaws are held together for 5 seconds. If the seal holds under the tension applied by the 35 gram weight, scaling is said to have taken place at the temperature under investigation.

The compositions of Examples 5, 6, 8 and 9 were tested under this procedure. All of these materials were coated on label paper at the rate of 4 pounds per ream. The composition of Example 5 demonstrated a sealing range of 70-140 C.; Example 6, 70120 (3.; Example 8, 70-l10 C.; Example 9, 70150 C. By way of comparsion, five heat-seal compositions widely used in the trade were tested. The broadest sealing range demonstrated by any of these five compositions was 80-110 C.

Label paper was coated with the composition described in Example 6 at 4 pounds per ream. The coatings were dried in an oven at 100 C. for a few minutes after which seals were made to cellulose acetate, rubber hydrochloride (Pliofilrn), to nitro cellulose coated cellophane, to uncoated (PT) cellophane, and to a film of polyvinylidene chloride polymer (Saran), to glass and to metal. Excellent bonds resulted, and when an attempt was made to remove the labels it was noted that the paper failed, but the bond remained intact. Similar results were obtained with the compositions described in Examples 3, 4, 5, 7 and 3. A 'ter one month the seals were examined again and no deterioration whatsoever was observed.

I claim as my invention:

1. A suspensoid in an aqueous medium of (a) from 2090% of a first polyamide melting withinthe approximate range of 130210 C. and being derived from a mixture of from -98% polymeric fat acids and from 215% of non-fatty polycarboxylic acid in which the carboxyl groups are separated by from 3 to 8 carbon atoms, and an aliphatic diamine and (b) from 10-80% of a second polyamide melting below C. and being derived from polymeric fat acids and an aliphatic polyamine, the amino groups primarily involved in the polyamide formation being separated by at least 3 atoms; the mixture of polyamides having an amine number of at least 5 and being dispersed in an aqueous medium by means of suflicient acid to produce a stable suspensoid.

2. A suspensoid in an aqueous medium of (a) from 4060% of a first polyamide melting within the approximate range of 2l0 C. and being derived from a mixture of from 85-98% polymeric fat acids and from 215% of non-fatty polycarboxylic acid in which the carboxyl groups are separated by from 3 to 8 carbon atoms, and an aliphatic diamine and (b) from 40-60% of a second polyamide melting below 100 C. and being derived from polymeric fat acids and an aliphatic polyamine, the amino groups primarily involved in the polyamide formation being separated by at least 3 atoms; the mixture of polyamides having an amine number of at least 5 and being dispersed in an aqueous medium by means of suflicient acid to produce a stable suspensoid.

3. A suspensoid in an aqueous medium of (a) from 2090% of a first polyamide melting within the approximate range of 130210 C. and being derived from a mixture of from 8598% polymeric fat acids and from 2-15 of sebacic acid, and an aliphatic diamine and (b) from 1080% of a second polyamide melting below 100 C. and being derived from polymeric fat acids and an aliphatic polyamine, the amino groups primarily involved in the polyamide formation being separated by at least 3 atoms; the mixture of polyamides having an amine number of at least 5 and being dispersed in an aqueous medium by means of sufiicient acid to produce a stable suspensoid.

4. A suspensoid in an aqueous medium of (a) from 2090% of a first polyamide melting within the approximate range of l30210 C. and being derived from a mixture of from 85-98% polymeric fat acids and from 2-15 of adipic acid, and an aliphatic diamine and (b) from 10-80% of a second polyamide melting below 100 C. and being derived from polymeric fat acids and an aliphatic polyamine, the amino groups primarily involved in the polyamide formation being separated by at least 3 atoms; the mixture of polyamides having an amine number of at least 5 and being dispersed in an aqueous medium by means of suflicient acid to produce a stable suspensoid.

5. A suspensoid in an aqueous medium of (a) from 20-80% of a first polyamide resin melting within the approximate range of 130210 C. and being derived from 85-98% of polymerized fat acids and from 2-15% of sebacic acid and ethylene diamine, and (b) from 1090% of a second polyamide resin melting below 100 C. and being derived from polymeric fat acids and diethylene triamine; the mixture of polyamide resins hav- 1! ing an amine number of at least and being dispersed in :an aqueous mediumby means of 'sufiicient acid to produce-a stable'susp'ensoid. g n -6. A suspensoid in an aqueous medium of (a) from -80% of a first polyamide resin melting within the approximate range of 130-210 C. and being derived from 98% of polymerized fat acids and from 2-15 'of adipic acid and ethylene diamine, and (b) from 10 of a second polyamide resin melting below ing-Van amine number of at least 10 and being dispersed in an aqueous medium by means of sufficient acid to produceastable suspensoid.

-7. A suspensoid 'in an aqueous medium of (affrom 4060% ofa first polyamide resin melting within the approximate range of -210" C. and being derived from 85-98% of polymerized fat acids and from 2-15 of sebacic acid and ethylene diamine, and (b) from 40- 60% of a second polyamide' resin melting below 100 C. and being derived from polymeric fat acids and diethylene triamine; the mixture of polyamideresins having an amine number of'at least '10, and b'eingldispersed in an aqueous medium by means of sufiicient acid tol produce a stable suspensoid. l V w 8. A suspensoid in an aqueous medium of '(a) from 40-60% of' a first polyamide resin melting tw'ithin the approximate range of 130-210" C. and being derived I from 85-98% of polymerized fat acids and from 215% ofadipic acid and ethylene diamine, and (5) from 60% of a second polyamide resin melting below l00 C, and being derived from polymeric fat acids and diduce a stable suspensoid.

No references cited. 

1. A SUSPENSOID IN AN AQUEOUS MEDIUM OF (A) FROM 20-90% OF A FIRST POLYAMIDE MELTING WITHIN THE APPROXIMATE RANGE OF 130-210* C. AND BEING DERIVED FROM A MIXTURE OF FROM 85-98% POLYMERIC FAT ACIDS AND FROM 2-1K% OF NON-FATTY POLYCARBOXYLIC ACID IN WHICH THE CARBOXYL GROUPS ARE SEPARATED BY FROM 3 TO 8 CARBON ATOMS, AND AN ALIPHATIC DIAMINE AND (B) FROM 10-80% OF A SECOND POLYAMIDE MELTING BELOW 100* C. AND BEING DERIVED FROM POLYMERIC FAT ACIDS AND AN ALIPHATIC POLYAMINE, THE AMINO GROUPS PRIMARILY INVOLVED IN THE POLYAMIDE FORMATION BEING SEPARAATED BY AT LEAST 3 ATOMS; THE MIXTURE OF POLYAMIDES HAVING AN AMINE NUMBER OF AT LEAST 5 AND BEING DISPERSED IN AN AQUEOUS MEDIUM BY MEANS OF SUFFICIENT ACID TO PRODUCE A STABLE SUSPENSOID. 